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Full text of "Text Book Of Mechanical Engineering"

Plate Girder.

4-35

one P Q is drawn at equal distance above E.    Then as before,
after drawing stress areas:

Upper area = 1-256x4-56= s "7 1

T ri                   J         J      J ' v = 5*45 average

Lower area = 2-102 x 2-44.= 5-2 J                    

Moment of resistance =/t x area x arm

= ij x 5-45 x 5-35 = 36-45 ton inches    
or by approximate formula = i\ x 6 x 5^= 38-4 ton inches.

, --- ^_

Momental Strength of Plate Girder (Fig, 391). The
rivets must  be  deducted in  tension  flange, but   they  aid the

resistance in compression,    The centre of figure (centroid) is then
found by taking moments of the parts round A,